Index: src/wp-admin/js/customize-widgets.js
===================================================================
--- src/wp-admin/js/customize-widgets.js	(revision 39941)
+++ src/wp-admin/js/customize-widgets.js	(working copy)
@@ -147,7 +147,6 @@
 
 		events: {
 			'input #widgets-search': 'search',
-			'keyup #widgets-search': 'search',
 			'focus .widget-tpl' : 'focus',
 			'click .widget-tpl' : '_submit',
 			'keypress .widget-tpl' : '_submit',